Re: [Ecryptfs-devel] [PATCH] ecryptfs: some inode attrs, and a question

From: hooanon05
Date: Sun Jan 18 2009 - 21:15:29 EST



> Yes, testing by d_unhashed() is best, I think.
> But all inode attributes are maintained by ecryptfs_interpose(), so you
> don't need to handle them.
>
> And I found another bug in ecryptfs_link().
> Here is a patch including that.

I forgot i_count.
Here is the fixed one.

J. R. Okajima

----------------------------------------------------------------------
refine ecryptfs_link()

ecryptfs_link() doesn't need to,,,
- copy i_nlink and i_size for the target inode since they are already
handled by ecryptfs_interpose(). (I don't know why i_size was
necessary)
- maintain dir attributes based upon the lower dir, instead of
lower_new_dentry. (another bug)
- several d_drop()s. do it only when the lower_new_dentry is d_drop()ed
by the lower fs or vfs_link() failed.
- testing lower_new_dentry->d_inode after vfs_link() succeeded.

Signed-off-by: J. R. Okajima <hooanon05@xxxxxxxxxxx>

diff -u -p -r1.1 inode.c
--- fs/ecryptfs/inode.c 19 Dec 2008 03:05:27 -0000 1.1
+++ fs/ecryptfs/inode.c 18 Jan 2009 05:22:35 -0000
@@ -405,10 +407,8 @@ static int ecryptfs_link(struct dentry *
struct dentry *lower_old_dentry;
struct dentry *lower_new_dentry;
struct dentry *lower_dir_dentry;
- u64 file_size_save;
int rc;

- file_size_save = i_size_read(old_dentry->d_inode);
lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
dget(lower_old_dentry);
@@ -416,23 +416,26 @@ static int ecryptfs_link(struct dentry *
lower_dir_dentry = lock_parent(lower_new_dentry);
rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
lower_new_dentry);
- if (rc || !lower_new_dentry->d_inode)
- goto out_lock;
- rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
- if (rc)
- goto out_lock;
- fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
- fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
- old_dentry->d_inode->i_nlink =
- ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
- i_size_write(new_dentry->d_inode, file_size_save);
-out_lock:
+ if (!rc) {
+ fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
+ fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
+ if (!d_unhashed(lower_new_dentry)
+ /* && lower_new_dentry->d_inode */) {
+ rc = ecryptfs_interpose(lower_new_dentry, new_dentry,
+ dir->i_sb, 0);
+ if (!rc) {
+ /* ecryptfs_interpose() doesn't increment */
+ atomic_inc(&inode->i_count);
+ goto out_lock; /* success */
+ }
+ }
+ }
+ out_drop:
+ d_drop(new_dentry);
+ out_lock:
unlock_dir(lower_dir_dentry);
dput(lower_new_dentry);
dput(lower_old_dentry);
- d_drop(lower_old_dentry);
- d_drop(new_dentry);
- d_drop(old_dentry);
return rc;
}

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